1. Field of the Invention
The present invention relates to an encapsulation cap, an organic electroluminescent device having the same, and a manufacturing method thereof. Particularly, the present invention relates to the encapsulation cap capable of preventing defects like sealant overflowing.
Also, the present invention relates to a mother glass substrate for manufacturing polyhedral encapsulation cap capable of forming a plurality of encapsulation caps having a structure capable of preventing defects like sealant overflowing on one substrate.
2. Description Of The Related Art
Organic electroluminescence is a phenomenon emitting a light having a predetermined wavelength by energy from exciton formed by recombination of an electron and a hole injected to an organic (low or high molecule) thin film through an anode and a cathode. And, an organic electroluminescent device is a display device using this light-emitting phenomenon.
The organic electroluminescent device generally uses an encapsulation cap made of metal or glass.
FIG. 1 is a sectional view showing the encapsulation structure of an organic electroluminescent device using the glass cap in the art.
In FIG. 1, an emitting part 2 of the organic electroluminescent device 10 is formed on a certain area of a substrate 1, and a glass cap 4 is bonded to the substrate 1 through a sealant 3 for separating the emitting part 2 from outer circumstance, that is, moisture or oxide.
Also, the inside of the glass cap 4 is concaved to be able to form a getter 5, that is, moisture absorbent.
Then, for the emitting part 2 not to directly contact with the glass cap 4 and the getter 5, a certain gap thicker than the emitting part 2 should be secured between the substrate 1 and the glass cap 4 oppositely disposed to each other. Therefore, a sealant 3 is generally manufactured by dispersing a spacer S in a liquid resin to maintain the gap between the substrate 1 and the glass cap 3.
But, when the spacer S is disposed between the substrate 1 and the glass cap 4, the thickness of a contacting part of the substrate 1 and the glass cap 4 is increased, thereby causing a problem that outside moisture or oxide may be permeated into inside of the organic electroluminescent device 10 through the sealant 3, and may erode the emitting part 2.
Also, in the process of distributing the sealant 3 onto the sealing surface of the encapsulation cap 4, if the amount of sealant 3 is not controlled precisely, especially in case of exceeding a proper amount of sealant 3, there may be a defect that the sealant 3 overflows inside or outside the sealing surface at the corner of the sealing surface bonded to the substrate 1 on which the encapsulation cap 4 and the emitting part 2 are formed.
Therefore, it has been necessary to develop an encapsulation cap having the structure capable of solving the defect like sealant overflowing occurred at the corner of the sealing surface.
FIG. 2 is a plan view showing a mother glass forming an organic electroluminescent device in the art.
In FIG. 2, in the mother glass substrate 20 in which a plurality of organic electroluminescent devices 10 are formed, a gap (B area) between one organic electroluminescent device and another organic electroluminescent device 10 is very small. Thus, a large amount of sealant 3 exists between the organic electroluminescent devices 10 by the sealant 3 flowed to outside.
Thus, the process of scribing each organic electroluminescent device 10 from the mother glass substrate 20 does not go smoothly.
Therefore, there has been a need for an encapsulation cap having the constitution capable of cutting off the flow of sealant 3 to outer area.